v1.50.0 - Maintenance release

Maintenance only, no bug fixes or new features

What's Changed

Development

• Python 3.9 Syntax Modernization by @tony in #953

Dependencies

• py(deps) libtmux: 0.39.0 -> 0.40.0 by @tony in #954

Full Changelog: v1.49.0...v1.50.0